Re: [PATCH V4 01/26] mm/mmap: Build protect protection_map[] with __P000

Christophe Leroy
2022-06-27T05:47:49Z

Le 24/06/2022 à 06:43, Anshuman Khandual a écrit :
> Build protect generic protection_map[] array with __P000, so that it can be
> moved inside all the platforms one after the other. Otherwise there will be
> build failures during this process. CONFIG_ARCH_HAS_VM_GET_PAGE_PROT cannot
> be used for this purpose as only certain platforms enable this config now.
>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>

> ---
> include/linux/mm.h | 2 ++
> mm/mmap.c | 2 ++
> 2 files changed, 4 insertions(+)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index bc8f326be0ce..47bfe038d46e 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -424,7 +424,9 @@ extern unsigned int kobjsize(const void *objp);
> * mapping from the currently active vm_flags protection bits (the
> * low four bits) to a page protection mask..
> */
> +#ifdef __P000
> extern pgprot_t protection_map[16];
> +#endif
>
> /*
> * The default fault flags that should be used by most of the
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 61e6135c54ef..b01f0280bda2 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -101,6 +101,7 @@ static void unmap_region(struct mm_struct *mm,
> * w: (no) no
> * x: (yes) yes
> */
> +#ifdef __P000
> pgprot_t protection_map[16] __ro_after_init = {
> [VM_NONE] = __P000,
> [VM_READ] = __P001,
> @@ -119,6 +120,7 @@ pgprot_t protection_map[16] __ro_after_init = {
> [VM_SHARED | VM_EXEC | VM_WRITE] = __S110,
> [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = __S111
> };
> +#endif
>
> #ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
> pgprot_t vm_get_page_prot(unsigned long vm_flags)